a) Technical Field of the Invention
The present invention relates to a motor-synchronous exciting brake structure, and in particular, by employing magnetism of the rotor to provide braking function without incorporating additional magnetic coils.
b) Description of the Prior Art
FIG. 1 is a conventional motor structure, wherein the securing seat 20 of the brake structure 2 is mounted to the end portion of the motor 1 after it passes through the rotor shaft 10. The securing seat 20 is provided with a plurality of guiding rods 21 and each of the individual rods 21 is provided in sequence with an urging element 22, a spring 24 and an exciting coil 23. An engaging section 11 is formed on the rotor shaft 10, and a pair of braking shoes 25 are provided between the securing seat 20 and the urging element 22. The exciting coil 23 and the motor 1 are joined together to a current distributor 26, such that the exciting coil 23 and the motor 1 are supplied with current synchronously or cut off from current supply synchronously.
As shown in FIGS. 2A and B, when the switch is initiated, the current distributor 26 provides current to the motor 1 and the exciting coil 23 such that the rotor shaft 10 of the motor 1 acted by the stator rotates. At the same time, the exciting coil 23 produces magnetism and the urging element 22 biases to the exciting coil 23 as a result of the magnetism. This will release the brake shoes 25, and the rotor shaft 10 rotates smoothly.
On the other hand, if the current supply is cut off, the exciting coil 23 does not produce magnetism to attract the urging element 22. As a result of the spring 24, the urging element 22 rapidly presses the brake shoes 25 from stop moving at the securing seat 20. As the rotor shaft 10 has lost its moving force, the rotor shaft 10 is immediately stopped, and the objective of braking is obtained.
The above conventional motor brake structure can provide a braking function but there are numerous drawbacks as follows:
1) Unstable braking force:
As the urging element 22 is achieved by the four springs 24 of the four guiding rods 21, the uneven action of the springs 24 may cause the urging element 22 to contact with the brake shoes 25 at one side. Thus, the braking force is not stable, and the brake shoes 25 may easily worn out, which affects the longevity of the brake shoes 25.
2) Erroneous Action:
The brake structure 2 and the motor 1 are respectively provided with a different exciting coil 23, and a current distributor 26 is employed to achieve the cut off current supply or to supply current, this will cause error action to the electronic components. The frequent ON-OFF current supply will damage the motor 1.
3) Braking time is longer:
The urging element 22 is secured by the spring 24. If the brake shoes 25 are worn out, the braking time taken for braking function is longer.
Accordingly, it is an object of the present invention to provide a motor-synchronous exciting brake structure, so that erroneous action of the brake structure is mitigated and the longevity of the brake structure is increased.
Yet another object of the present invention is to provide a motor-synchronous exciting brake structure, wherein the stability of braking is improved and good braking effect can be obtained
Another flier object of the present invention is to provide a motor-synchronous exciting brake structure, wherein the braking time is shortened and safety is greatly increased.
One aspect of the present invention is to provide a motor-synchronous exciting brake structure having a housing containing a stator and a rotor located at the center of the stator, the two ends of the housing being respectively mounted with an end cap, and the rotor shaft of the rotor being mounted with a brake structure which is used to brake the rotor, characterized in that the brake structure is provided with a floating element slidably located at the rotor shaft, and the end face of the floating element, corresponding to the end cap, is provided with a plurality of brake blocks for braking purpose, and a triggering element is slidably mounted within the floating element, an elastic element is urged by the triggering element and the floating element, and further, the end face of the triggering element, corresponding to the rotor, is formed with two corresponding guiding slots, and one side of the guiding slot is provided with a sloping face, wherein the sloping face is inclined toward the end face, the other end of the floating element is a limiting plate to restrict the triggering element, the circumference of a center hole on the limiting plate is provided with two corresponding extension slots, and a triggering spring is located between the rotor and the limiting plate; the rotor shaft is provided with a limiting rod and a guiding rod, wherein the limiting rod is engaged at the inner edge of the limiting plate, and the guiding rod is correspondingly mounted at the guiding slot of the triggering element, thereby a stable brake with a short braking distance motor synchronous exciting brake structure is formed.
Other objection and advantages of the invention will be apparent from and elucidated with reference to the embodiment described hereinafter.